<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>我们都是好孩子</title>
	<style>
		div {
			width: 600px;
			height: 600px;
			margin: 0 auto;
			background-color: red;
			border-color: blue;
		}
	</style>
</head>
<body>
	<div></div>
</body>
</html>